1. Field of the Invention
The present invention relates to the recovery of elastomers. More particularly, the present invention relates to co-grinding an elastomer and an additive in a slurry to produce ground elastomer particles.
2. Description of the Related Art
In recycling and reusing rubber materials, it is generally known to decrease the size of such rubber materials to small ground rubber particles (i.e., particles of irregular outline that pass through a minus 80 mesh or through a minus 50-mesh or finer). Such particles can be chemically more reactive and mechanically easier to dissolve into various mixes.
A variety of rubber products (e.g., natural rubber, synthetic rubber, vulcanized rubber, automotive tire scrap, etc.) may be reduced to ground rubber particles. Known methods for producing rubber of a decreased size include cryogenic cracking of the rubber. Other known methods include the milling of the rubber between horizontal grinding stones in a horizontal grinding mill. Such milling techniques have been developed in the flour, paper pulp industry and the paint pigment compounding industries. Such milling techniques include grinding the rubber between opposed milling wheels, such that one wheel is fixed and the other wheel rotates relative to the fixed wheel. Such known milling techniques include pressing the two wheels against a rubber slurry, such that the rubber is ground to a fine state (i.e., powder) in a single pass. However, such known milling methods have the disadvantage of creating friction and introducing energy to the slurry, which may increase the temperature of the slurry. Increased slurry temperatures may cause "flash over" in which the slurry becomes a largely dry rubber mass that inhibits grinding. Such known milling methods further have the disadvantage of not producing a uniformly fine rubber powder that passes through a minus 50-mesh.
Accordingly, it would be advantageous to have a method for converting an elastomer to a ground particle. It would also be advantageous to have a method to convert an elastomer to a decreased size that decreases soak time of the elastomer. It would also be advantageous to have a method to convert an elastomer to a decreased size that decreases grinding time of the elastomer. It would also be advantageous to have a method that converts an elastomer to a decreased size carried out at a relatively low temperature of an elastomer slurry. It would also be advantages to have an elastomer that chemically combines with an additive to modify the physical properties of the elastomer.